In road construction, chargers are used to supply road finishing machines with bituminous paving material. In road construction, charger vehicles drive ahead of the road finishing machines to ensure that sufficient paving material is continuously available for the road finishing machine during the asphalting process. Charger vehicles comprise a material bunker in which paving material transported from trucks to the road construction site is intermediately stored. Conveyor means, for example conveyor belts, are guided away from the material bunker and supply the paving material out of the material bunker to a following road finishing machine. During the transport of the viscous paving material, the conveyor belts of the chargers are subjected to high mechanical and thermal stresses. Charger vehicles are expected to supply the paving material to be conveyed to the road finishing machine at a certain height. Therefore, the conveyor belts of the chargers are disposed to be vertically adjustable. In most cases, the conveyor belts can be pivoted about a pivot axis extending through a deflection roller in a vertically adjustable manner, so that a desired discharge height is reached at the discharge place. However, it showed in practice that an inclination of the conveyor belt is only possible within limits to reach a desired discharge height. The reason for this is that with an excessively steep position of the conveyor belt, transporting capacity is affected. For example, with an excessively steep position, paving material might be shifted to the rear and not be conveyed into the desired direction. Moreover, the conveyor belt might no longer be operated at all speeds with an excessively steep position.
EP 0 957 205 B1 describes a road finishing machine or a charger system, respectively. Here, a road finishing machine, which is simultaneously designed as a charger, drives ahead of another road finishing machine. Via a conveyor assembly consisting of two conveyor belts, bituminous paving material can be supplied by a first conveyor belt to a screed of the first road finishing machine or be poured towards the following road finishing machine by a second conveyor belt. To supply the viscous paving material to the following road finishing machine at a certain height, the second conveyor belt of the first road finishing machine or charger is arranged to be vertically adjustable. To be able to adjust the discharge height of the vertically adjustable conveyor belt, the conveyor belt is suspended at the chassis to be pivoted about an axis of a front deflection roller.
DE 298 12 115 U1 relates to a transfer unit for transporting bound and non-bound building materials into paving units, preferably for transporting mixed material into paving units for asphalt layers. The transfer unit comprises a conveyor assembly consisting of two conveyor belts, wherein one belt of the transfer unit is designed as a slewing belt which can be vertically adjusted to realize different conveyor heights. The vertical adjustment of the belt is effected between 15° and 25° with respect to the horizontal line. Slewing motions of the conveyor belts are continuously variable hydraulically and can be well modulated. It is also possible to actuate the slewing motion via other means, such as cable winches, toothed racks or mechanical gear mechanisms. However, during the slewing motion or the vertical adjustment of the conveyor belts, one has to take care that an excessively steep position affects the transporting capacity of the conveyor belts.
The object underlying the invention is to provide a charger system which reaches a desired discharge height using simple constructive means without affecting transporting capacity.
This object is achieved with the present invention.
The invention describes a slewing belt mounting suited for being attached to a charger. By the attachment of the slewing belt mounting, a given discharge height of the paving material can be achieved.
The slewing belt mounting is attached to the frame of the charger. According to the invention, the slewing belt mounting comprises a cantilever arm mounted at the frame of the charger, a pivot arm which is pivotally connected to the cantilever arm, and a conveyor belt which is connected to the pivot arm. It is characteristic of the invention that the slewing belt mounting comprises at least one lifting element, such as a hydraulic cylinder, a cable winch, a toothed rack, a gear mechanism, or the like which is fixed with a first end at the frame and with a second end at the cantilever arm, wherein the cantilever arm is vertically adjustable by the lifting element. Below, the lifting element will be referred to as hydraulic cylinder in each case.
It is advantageous to be able to introduce the reaction power of the conveyor belt of the slewing belt mounting above the cantilever arm directly into the frame of the charger. Since the slewing belt mounting is not connected with the frame of the conveyor belt of the charger, oscillating influences of the charger conveyor belt are not transmitted to the conveyor belt of the slewing belt mounting. In the slewing belt mounting, the cantilever arm can be vertically adjusted into a working position by the hydraulic cylinder. Thus, the discharge height of the paving material of the slewing belt mounting can be directly influenced by the position of the cantilever arm. As an alternative, the conveyor belt of the slewing belt mounting can be tilted to adjust the discharge height. Here, it should be taken care that with an excessively steep position of the conveyor belt, less transporting capacity is obtained. It is therefore advantageous to first pilot a prescribed discharge height by a vertical adjustment of the cantilever arm. Moreover, by the vertical adjustment of the cantilever arm, a maximum passing height in the working position and a maximum transport height in a transport position are not exceeded.
In a suitable embodiment, the hydraulic cylinder is rotatably fixed with the first end to the frame and with the second end to the cantilever arm. By this, the cantilever arm can be particularly flexibly adjusted vertically.
Preferably, the pivot arm is movable about a pivot axis. By the possibility of pivoting the pivot arm together with the conveyor belt, different discharge places can be determined for the paving material.
Preferably, the slewing belt mounting is in a transport position when the hydraulic cylinder is retracted. In particular in the retracted state, the hydraulic cylinder offers a stable mounting for the cantilever arm. It is advantageous to secure the cantilever arm by a pin when the hydraulic cylinder is extended or retracted, respectively.
For a safe transport, the slewing belt mounting does not exceed a transport height of 3.10 m in the transport position. Bridge underpasses can be safely traversed thereby.
The cantilever arm is preferably mounted to be movable about a pivot axis. The cantilever arm can be pivoted about the pivot axis to adjust a prescribed discharge height for the conveyor belt of the slewing belt mounting.
In a suitable embodiment, the cantilever arm is mounted to be pivotable from the transport position about the pivot axis. By this, the discharge height can be varied as desired.
It is advantageous for the conveyor belt to comprise pivot positions with a pivoting radius of up to 180°. By this, not only the discharge height, but also the discharge place can be varied with the slewing belt mounting.
In a further advantageous embodiment, the pivot arm comprises a first section and a second section, the two sections being firmly connected to each other. By the first section, the pivot arm is pivotally connected with the cantilever arm, and by the second section, the conveyor belt of the slewing belt mounting can be stably mounted.
A stable attachment of the slewing belt mounting at the charger frame can be supported by the cantilever arm comprising struts. Compressive and tensile forces can be effectively absorbed by the struts.
In a suitable embodiment, the conveyor belt of the slewing belt mounting comprises a receiving portion that projects under the cantilever arm or is offset with respect to the latter. Thereby, the torques acting on the cantilever arm are reduced thus relieving the cantilever arm. It is also advantageous for the pivot axis of the pivot arm to extend through the receiving portion. By this, a mechanical relief of the pivot arm and the cantilever arm is achieved during pivoting.
Preferably, charger material can in practice fall onto the receiving portion of the conveyor belt in any pivot position, where the conveyor belt can accept and convey charger material even during pivoting. It is conceivable that thereby several following road finishing machines are charged with paving material from the slewing belt mounting. A drive of the road finishing machine and the charger vehicle offset in parallel with respect to each other also becomes possible thereby.
In another embodiment of the invention, the pivot axis of the pivot arm extends through the discharge point of the material that is transported by the conveyor assembly of the charger vehicle onto the conveyor belt of the pivot arm. It is thus ensured that during the rotation of the slewing belt, the material falls onto the slewing belt and not onto the floor if the slewing belt is rotated too far to the outside.
In another embodiment, the slewing belt mounting comprises a tensioning element that is tensioned between the pivot arm and the conveyor arm. Possible tensioning elements are, for example, chains or ropes with or without an additional hydraulic cylinder. It is advantageous for the tensioning element to be fixed to an upper end of the first section of the pivot arm. Moreover, by the tensioning element, the conveyor belt of the slewing belt mounting can be pivoted about a pivot axis at a first deflection roller, and thus the discharge height can be varied.
One can take care of a compact attachment of the slewing belt mounting at the frame of a charger if the cantilever arm and the hydraulic cylinder are arranged within the frame of the charger.
In an extended state of the hydraulic cylinder, the cantilever arm can be lifted beyond a height of 3.10 m.
The slewing belt mounting can be fixed to charger vehicles like modules. This permits to quickly and easily install or remove the slewing belt mounting at the charger vehicle.
In a suitable embodiment, during the lifting of the cantilever arm, the inclination of the conveyor belt can be changed. The conveyor belt is, for example, lowered when the cantilever arm is lifted by the hydraulic cylinder.